The primary goal of this research is to identify significant modifiable factors (i.e., diet, lifestyle factors, etc.) and novel risk factors that may predict the risk for GDM and contribute to the prevention of GDM. Within the common theme of insulin resistance and secretion, several important diet and lifestyle associations with GDM have been successfully identified in this effort based on data from the Nurses' Health Study II and the NICHD Fetal Growth Studies. In the past year, we have identified several new risk factors including dietary protein intakes, potato consumption, history of infertility, history of depression, sleep duration, and environmental chemicals such as perfluorooctanoic acid etc. These papers were presented in the Society of Maternal and Fetal Medicine meeting, Annual Scientific Meeting of American Diabetes Association, Society for Epidemiologic Research, and Society for Pediatric and Perinatal Research. We published several important papers on this topic as well. Several papers are submitted and under review.